///////////////////////////// executable code ////////////////////////////////
// This function reads data from the specified stream in search of a valid
// WavPack 4.0 audio block. If this fails in 1 megabyte (or an invalid or
// unsupported WavPack block is encountered) then an appropriate message is
// copied to "error" and NULL is returned, otherwise a pointer to a
// WavpackContext structure is returned (which is used to call all other
// functions in this module). This can be initiated at the beginning of a
// WavPack file, or anywhere inside a WavPack file. To determine the exact
// position within the file use WavpackGetSampleIndex(). Also,
// this function will not handle "correction" files, plays only the first
// two channels of multi-channel files, and is limited in resolution in some
// large integer or floating point files (but always provides at least 24 bits
// of resolution).
public static WavpackContext WavpackOpenFileInput(System.IO.BinaryReader infile)
{
WavpackContext wpc = new WavpackContext();
WavpackStream wps = wpc.stream;
wpc.infile = infile;
wpc.total_samples = -1;
wpc.norm_offset = 0;
wpc.open_flags = 0;
// open the source file for reading and store the size
while (wps.wphdr.block_samples == 0)
{
wps.wphdr = read_next_header(wpc.infile, wps.wphdr);
if (wps.wphdr.status == 1)
{
wpc.error_message = "not compatible with this version of WavPack file!";
wpc.error = true;
return(wpc);
}
if (wps.wphdr.block_samples > 0 && wps.wphdr.total_samples != -1)
{
wpc.total_samples = wps.wphdr.total_samples;
}
// lets put the stream back in the context
wpc.stream = wps;
if ((UnpackUtils.unpack_init(wpc)) == Defines.FALSE)
{
wpc.error = true;
return(wpc);
}
} // end of while
wpc.config.flags = wpc.config.flags & ~0xff;
wpc.config.flags = wpc.config.flags | (wps.wphdr.flags & 0xff);
wpc.config.bytes_per_sample = (int)((wps.wphdr.flags & Defines.BYTES_STORED) + 1);
wpc.config.float_norm_exp = wps.float_norm_exp;
wpc.config.bits_per_sample = (int)((wpc.config.bytes_per_sample * 8) - ((wps.wphdr.flags & Defines.SHIFT_MASK) >> Defines.SHIFT_LSB));
if ((wpc.config.flags & Defines.FLOAT_DATA) > 0)
{
wpc.config.bytes_per_sample = 3;
wpc.config.bits_per_sample = 24;
}
if (wpc.config.sample_rate == 0)
{
if (wps.wphdr.block_samples == 0 || (wps.wphdr.flags & Defines.SRATE_MASK) == Defines.SRATE_MASK)
{
wpc.config.sample_rate = 44100;
}
else
{
wpc.config.sample_rate = sample_rates[(int)((wps.wphdr.flags & Defines.SRATE_MASK) >> Defines.SRATE_LSB)];
}
}
if (wpc.config.num_channels == 0)
{
if ((wps.wphdr.flags & Defines.MONO_FLAG) > 0)
{
wpc.config.num_channels = 1;
}
else
{
wpc.config.num_channels = 2;
}
wpc.config.channel_mask = 0x5 - wpc.config.num_channels;
}
if ((wps.wphdr.flags & Defines.FINAL_BLOCK) == 0)
{
if ((wps.wphdr.flags & Defines.MONO_FLAG) != 0)
{
wpc.reduced_channels = 1;
}
else
{
wpc.reduced_channels = 2;
}
}
return(wpc);
}
// Unpack the specified number of samples from the current file position.
// Note that "samples" here refers to "complete" samples, which would be
// 2 longs for stereo files. The audio data is returned right-justified in
// 32-bit longs in the endian mode native to the executing processor. So,
// if the original data was 16-bit, then the values returned would be
// +/-32k. Floating point data will be returned as 24-bit integers (and may
// also be clipped). The actual number of samples unpacked is returned,
// which should be equal to the number requested unless the end of fle is
// encountered or an error occurs.
internal static long WavpackUnpackSamples(WavpackContext wpc, int[] buffer, long samples)
{
WavpackStream wps = wpc.stream;
long samples_unpacked = 0, samples_to_unpack;
int num_channels = wpc.config.num_channels;
int bcounter = 0;
int buf_idx = 0;
int bytes_returned = 0;
while (samples > 0)
{
if (wps.wphdr.block_samples == 0 || (wps.wphdr.flags & Defines.INITIAL_BLOCK) == 0 || wps.sample_index >= wps.wphdr.block_index + wps.wphdr.block_samples)
{
wps.wphdr = read_next_header(wpc.infile, wps.wphdr);
if (wps.wphdr.status == 1)
{
break;
}
if (wps.wphdr.block_samples == 0 || wps.sample_index == wps.wphdr.block_index)
{
if ((UnpackUtils.unpack_init(wpc)) == Defines.FALSE)
{
break;
}
}
}
if (wps.wphdr.block_samples == 0 || (wps.wphdr.flags & Defines.INITIAL_BLOCK) == 0 || wps.sample_index >= wps.wphdr.block_index + wps.wphdr.block_samples)
{
continue;
}
if (wps.sample_index < wps.wphdr.block_index)
{
samples_to_unpack = wps.wphdr.block_index - wps.sample_index;
if (samples_to_unpack > samples)
{
samples_to_unpack = samples;
}
wps.sample_index += samples_to_unpack;
samples_unpacked += samples_to_unpack;
samples -= samples_to_unpack;
if (wpc.reduced_channels > 0)
{
samples_to_unpack *= wpc.reduced_channels;
}
else
{
samples_to_unpack *= num_channels;
}
bcounter = buf_idx;
while (samples_to_unpack > 0)
{
buffer[bcounter] = 0;
bcounter++;
samples_to_unpack--;
}
buf_idx = bcounter;
continue;
}
samples_to_unpack = wps.wphdr.block_index + wps.wphdr.block_samples - wps.sample_index;
if (samples_to_unpack > samples)
{
samples_to_unpack = samples;
}
UnpackUtils.unpack_samples(wpc, buffer, samples_to_unpack, buf_idx);
if (wpc.reduced_channels > 0)
{
bytes_returned = (int)(samples_to_unpack * wpc.reduced_channels);
}
else
{
bytes_returned = (int)(samples_to_unpack * num_channels);
}
buf_idx += bytes_returned;
samples_unpacked += samples_to_unpack;
samples -= samples_to_unpack;
if (wps.sample_index == wps.wphdr.block_index + wps.wphdr.block_samples)
{
if (UnpackUtils.check_crc_error(wpc) > 0)
{
wpc.crc_errors++;
}
}
if (wps.sample_index == wpc.total_samples)
{
break;
}
}
return(samples_unpacked);
}
